Neural - Pons Development

Embryology - 8 May 2024        Expand to Translate
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Introduction

Fetal Head showing developing Pons.

Adult brain showing Pons.

(Latin, pons = "bridge") A brain stem region within the central nervous system, anatomically lying above the medulla before the nervous system becomes the spinal cord.

Neural development is one of the earliest systems to begin and the last to be completed after birth. This development generates the most complex structure within the embryo and the long time period of development means in utero insult during pregnancy may have consequences to development of the nervous system.

The early central nervous system begins as a simple neural plate that folds to form a groove then tube, open initially at each end. Failure of these opening to close contributes a major class of neural abnormalities (neural tube defects).

Within the neural tube stem cells generate the 2 major classes of cells that make the majority of the nervous system : neurons and glia. Both these classes of cells differentiate into many different types generated with highly specialized functions and shapes. This section covers the establishment of neural populations, the inductive influences of surrounding tissues and the sequential generation of neurons establishing the layered structure seen in the brain and spinal cord.

• Neural development beginnings quite early, therefore also look at notes covering Week 3 neural tube and Week 4 early nervous system.

Some Recent Findings

Development of the pons in human fetuses "Morphometric and histological studies of the pons were performed by light microscopy in 28 cases of externally normal human fetuses ranging from 90 to 246 mm in crown-rump length (CRL) and from 13 to 28 weeks of gestation." Cerebellar haemorrhages and pons development in extremely low birth weight infants "The anteroposterior diameter of the pons was measured manually on the midline sagittal T1 Magnetic Resonance Image ...Cerebellar haemorrhages seem to affect the development of the pons in extremely low birth weight (ELBW) with the youngest gestational age (GA)." Development of the human fetal pons: in utero ultrasonographic study "By using the transfontanel approach, evaluation of the fetal pons is feasible via the mid-sagittal plane. The nomograms developed and the ratio to fetal vermis provides reference data that may be helpful when evaluating anomalies of the brainstem."

More recent papers

This table allows an automated computer search of the external PubMed database using the listed "Search term" text link. This search now requires a manual link as the original PubMed extension has been disabled. The displayed list of references do not reflect any editorial selection of material based on content or relevance. References also appear on this list based upon the date of the actual page viewing. References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability. More? References | Discussion Page | Journal Searches | 2019 References | 2020 References Search term: Pons Embryology <pubmed limit=5>Pons Embryology</pubmed>

Development Overview

Neuralation begins at the trilaminar embryo with formation of the notochord and somites, both of which underly the ectoderm and do not contribute to the nervous system, but are involved with patterning its initial formation. The central portion of the ectoderm then forms the neural plate that folds to form the neural tube, that will eventually form the entire central nervous system.

Early developmental sequence: Epiblast - Ectoderm - Neural Plate - Neural groove and Neural Crest - Neural Tube and Neural Crest

Neural Tube Development

Neural Tube	Primary Vesicles	Secondary Vesicles	Adult Structures
week 3	week 4	week 5	adult
neural plate neural groove neural tube Brain	prosencephalon (forebrain)	telencephalon	Rhinencephalon, Amygdala, hippocampus, cerebrum (cortex), hypothalamus‎, pituitary | Basal Ganglia, lateral ventricles
		diencephalon	epithalamus, thalamus, Subthalamus, pineal, posterior commissure, pretectum, third ventricle
	mesencephalon (midbrain)	mesencephalon	tectum, Cerebral peduncle, cerebral aqueduct, pons
	rhombencephalon (hindbrain)	metencephalon	cerebellum
		myelencephalon	medulla oblongata, isthmus
spinal cord, pyramidal decussation, central canal

Early Brain Vesicles

Primary Vesicles

Secondary Vesicles

Adult Pons MRI

A T1-weighted sagittal MR image from a control subject, showing the midline structures of the posterior cranial fossa and the brainstem and the cerebellum. d + e = length of clivus S = sphenooccipital synchondrosis d = length of basisphenoid between the top of the dorsum sellae and the sphenooccipital synchondrosis of the clivus e = length of the basiocciput between the synchondrosis and the basion b = length of the hindbrain between the midbrain-pons junction and the medullocervical junction a = angle of the cerebellar tentorium to Twining's line c = length of cerebellar hemisphere DS = top of the dorsum sellae IOP = internal occipital protuberance OP = opisthion; IOP to OP = length of supraocciput B = basion; TW = Twining's line McR (B to OP) = McRae's line

Images

Historic Images

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  Fig. 677. Brain (lateral view)

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  Fig. 678. Brain - Schematic representation of the chief ganglionic categories (I to V).

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  Cerebellum

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  Cerebellum, Pons and Fourth Ventricle

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References

Reviews

<pubmed>20483389</pubmed>

Articles

<pubmed>11461149</pubmed> <pubmed>9512304</pubmed>

Search PubMed

Search Pubmed: Pons Embryology | Pons Development

External Links

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Glossary Links

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Cite this page: Hill, M.A. (2024, May 8) Embryology Neural - Pons Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Neural_-_Pons_Development

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G